An image-combining device comprising of a polarizing beam-splitter, two waveplates and two reflective micro-electro-mechanical display panels is described. It combines images with orthogonally polarized light. Projection display apparatus having such image-combining device(s) are used to project two-dimensional or three-dimensional images with orthogonally polarized light.
Legal claims defining the scope of protection, as filed with the USPTO.
1. A projection display apparatus comprising: first and second reflective light modulators for receiving incident light beams and impressing first and second images on corresponding returned light beams, each of said first and second reflective light modulators having light reflective pixel elements pivotal about respective rotation axes that are aligned in an alignment direction; a polarizing beam splitter having a beam splitting surface reflecting incident light in a first polarization as a reflected beam and transmitting incident light in a second polarization as a transmitted beam, a first port for receiving an incident light beam having said first and second polarizations, second and third ports for directing said reflected and transmitted beams toward said respective first and second reflective light modulators, said second and third ports also receiving first and second returned beams reflected by said respective first and second light modulators carrying said respective first and second images, and a fourth port for outputting a combined image beam comprising said first and second returned beams for projection onto a display screen; a first waveplate, placed between said second port of said polarizing beam-splitter and said first reflective light modulator, for converting light of said first polarization to said second polarization, whereby said reflected beam from said first reflective light modulator has said second polarization after passing through said first waveplate; and a second waveplate placed between said third port of said polarizing beam-splitter and said second reflective light modulator for converting light of said second polarization to said first polarization, whereby said reflected beam from said second reflective light modulator has said first polarization after passing through said second waveplate; and wherein said polarizing beam splitter has an incident plane defined by the normal of said beam splitting surface and said returned light beams carrying said impressed first and second images at said beam splitting surface; wherein said first and second light modulators are aligned so that the corresponding alignment directions of said first and second said light modulators are projected on to said fourth port as a common alignment direction; wherein said incident plane and said common alignment direction form an angle γ; and wherein said polarizing beam-splitter and said first and second reflective light modulators are oriented such that the angle γ is 0°≦γ≦45°.
2. A projection display apparatus as claimed in claim 1 , wherein said reflective light modulators are micro-electro-mechanical mirror arrays.
3. A projection display apparatus as claimed in claim 2 , wherein said polarizing beam splitter is selected from the group consisting of: the type employing thin film interference and the type employing thin film interference and frustrated total internal reflection.
4. A projection display apparatus as claimed in claim 3 , wherein said first and second images are selected from the group consisting of: identical two-dimensional images in a 2D display mode and left- and right-eye images in a stereoscopic 3D display mode.
5. A projection display apparatus as claimed in claim 2 , wherein said second reflective light modulator is selected such that the rotation axes of the pixel elements are mirror images of the rotation axes of the pixel elements of said first reflective light modulator.
6. A projection display apparatus as claimed in claim 2 , wherein said first and second reflective light modulator comprise micromirrors arranged as a rectangular panel, and the rotation axes of said micromirrors are oriented vertically with respect to said panel.
7. A projection display apparatus as claimed in claim 1 , wherein a plate mirror is located between said first reflective light modulator and said second port of said polarizing beam-splitter.
8. A projection display apparatus as claimed in claim 1 , wherein a plate mirror is located between said second reflective light modulator and said third port of said polarizing beam-splitter.
9. A projection display apparatus as claimed in claim 1 , wherein a prism mirror is located between said first reflective light modulator and said second port of said polarizing beam-splitter, and a matching prism is located between said second reflective light modulator and said third port of said polarizing beam-splitter.
10. A projection display apparatus as claimed in claim 1 , wherein a prism mirror is located between said second reflective light modulator and said third port of said polarizing beam-splitter and a matching prism is located between said first reflective light modulator and said second port of said polarizing beam-splitter.
11. A projection display apparatus as claimed in claim 7 , wherein said first and second reflective light modulators are identical to each other.
12. A projection display apparatus as claimed claim 1 , wherein the alignment of said first and second light modulators is such that the projections of the corresponding pixel elements of each light modulator onto said fourth port are coincident to permit the image from each light modulator to be projected onto said display screen as a common image.
13. A projection display apparatus as claimed in claim 1 , wherein a waveplate is located downstream of the fourth port of said polarizing beam-splitter to convert the polarization states of said returned light beams having said impressed first and second images from linear polarized states to circular polarized states.
14. A projection display apparatus comprising: a) at least two subsystems, each subsystem processing light of a different color and comprising: (i) first and second reflective light modulators for receiving incident light beams and impressing first and second images on corresponding returned light beams; and (ii) a polarizing beam splitter having a beam splitting surface reflecting incident light in a first polarization as a reflected beam and transmitting incident light in a second polarization as a transmitted beam, a first port for receiving an incident light beam having said first and second polarizations, second and third ports for directing said reflected and transmitted beams toward said respective first and second reflective light modulators, said second and third ports also receiving first and second returned beams reflected by said respective first and second light modulators carrying said respective first and second images, and a fourth port for outputting a combined image beam comprising said first and second returned beams for projection onto a display screen; (iii) a first waveplate, placed between said second port of said polarizing beam-splitter and said first reflective light modulator, for converting light of said first polarization to said second polarization, whereby said reflected beam from said first reflective light modulator has said second polarization after passing through said first waveplate; (iv) a second waveplate placed between said third port of said polarizing beam-splitter and said second reflective light modulator for converting light of said second polarization to said first polarization, whereby said reflected beam from said second reflective light modulator has said first polarization after passing through said second waveplate; and b) a color combiner for combining the output beams of the respective subsystems into a common output beam containing more than one color for projection onto a display screen.
15. A projection display system as claimed in claim 14 , wherein said light modulators are micro-electro-mechanical mirror arrays.
16. A projection display system as claimed in claim 14 , comprising three said subsystems, each corresponding to a primary color, wherein said display system provides full color projection images.
17. A projection display system as claimed in claim 14 , wherein said color combiner comprises a Philips prism.
18. A projection display system as claimed in claim 14 , wherein said color combiner comprises an X cube.
19. A projection display system as claimed in claim 14 , wherein the polarizing beam splitter associated with each subsystem is in the shape of a cube and is associated with a respective light source having a color corresponding to the color processed by that subsystem.
20. A projection display apparatus as claimed in claim 14 , wherein said polarizing beam splitter in each said subsystem is selected from the group consisting of: the type employing thin film interference and the type employing thin film interference and frustrated total internal reflection.
21. A projection display apparatus as claimed in claim 14 , wherein said first and second images in each said subsystem are selected from the group consisting of: identical two-dimensional images in a 2D display mode and left- and right-eye images in a stereoscopic 3D display mode.
22. A projection display apparatus as claimed in claim 14 , wherein in each said subsystem each of said first and second reflective light modulators have light reflective pixel elements pivotal about respective rotation axes that are aligned in an alignment direction, said polarizing beam splitter has an incident plane defined by the normal of said beam splitting surface and said returned light beams having said impressed first and second images at said beam splitting surface, said first and second light modulators are aligned so that the corresponding alignment directions of said first and second said light modulators are projected on to said fourth port as a common alignment direction; said incident plane and said common alignment direction form an angle γ; and said polarizing beam-splitter and said first and second reflective light modulators are oriented such that the angle γ is 0°≦γ≦45°.
23. A projection display apparatus as claimed in claim 14 , comprising a common broadband light source, a beam splitter arrangement for directing respective incident beams from said broadband source into each said subsystem, and a color filter in each said incident beam for transmitting to the associated subsystem the color associated with that subsystem.
24. A projection display apparatus as claimed in claim 14 , comprising a separate light source associated with each said subsystem.
25. A projection display apparatus as claimed in claim 14 , wherein a waveplate is located downstream of the fourth port of said polarizing beam-splitter to convert the polarization states of said returned light beams having said impressed first and second images from linear polarized states to circular polarized states.
26. A projection display apparatus comprising: a) at least three subsystems, each subsystem processing light of a different color and comprising: (i) first and second reflective light modulators for receiving incident light beams and impressing first and second images on corresponding returned light beams, each of said first and second reflective light modulators having light reflective pixel elements pivotal about respective rotation axes that are aligned in an alignment direction; (ii) a polarizing beam splitter having a beam splitting surface reflecting incident light in a first polarization as a reflected beam and transmitting incident light in a second polarization as a transmitted beam, a first port for receiving an incident light beam having said first and second polarizations, second and third ports for directing said reflected and transmitted beams toward said respective first and second reflective light modulators, said second and third ports also receiving first and second returned beams reflected by said respective first and second light modulators carrying said respective first and second images, and a fourth port for outputting a combined image beam comprising said first and second returned beams for projection onto a display screen; (iii) a first waveplate, placed between said second port of said polarizing beam-splitter and said first reflective light modulator, for converting light of said first polarization to said second polarization, whereby said reflected beam from said first reflective light modulator has said second polarization after passing through said first waveplate; and (iv) a second waveplate placed between said third port of said polarizing beam-splitter and said second reflective light modulator for converting light of said second polarization to said first polarization, whereby said reflected beam from said second reflective light modulator has said first polarization after passing through said second waveplate; and (v) wherein said polarizing beam splitter has an incident plane defined by the normal of said beam splitting surface and said returned light beams having said impressed first and second images at said beam splitting surface; (vi) wherein said first and second light modulators are aligned so that the corresponding alignment directions of said first and second said light modulators are projected on to said fourth port as a common alignment direction; (vii) wherein said incident plane and said common alignment direction form an angle γ; and (vii) wherein said polarizing beam-splitter and said first and second reflective light modulators are oriented such that the angle γ is 0°≦γ≦45°; and b) a color combiner for combining the output beams of the respective subsystems into a common output beam containing said at least three colors for projection onto a display screen to provide a full color display.
27. A projection display apparatus as claimed in claim 26 , wherein said reflective light modulators are micro-electro-mechanical mirror arrays.
28. A projection display apparatus as claimed in claim 26 , wherein said first and second images in each said subsystem are selected from the group consisting of: identical two-dimensional images in a 2D display mode and left- and right-eye images in a stereoscopic 3D display mode.
29. A projection display apparatus as claimed in claim 26 , wherein said polarizing beam splitter is selected from the group consisting of the type employing thin film interference and the type employing thin film interference and frustrated total internal reflection.
30. A projection display apparatus as claimed in claim 26 , wherein a waveplate is located downstream of the fourth port of said polarizing beam-splitter to convert the polarization states of said returned light beams having said impressed first and second images from linear polarized states to circular polarized states.
Cooperative Patent Classification codes for this invention. Click any code to explore related patents in that topic.
June 28, 2007
April 6, 2010
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